Radioactivity - The Changing Arctic Environment: The Arctic Messenger - page 59

The Kara Sea disposal sites for the 16 marine reactors and low- and intermediate-
level solid radioactive waste varied in depth from 12 to 380 m. The icebreaker re-
actors and part of their spent nuclear fuel were reportedly disposed of in Tsivolka
Fjord at an estimated depth of 50 m.

That February 1993 meeting at Holmenkollen marked the birth of the International Arctic
Sea Assessment Programme (IASAP), organised by the IAEA with cooperation from the
governments of Norway and the Russian Federation. It first assessed the risks to humans
associated with radioactive waste dumped in the Kara and Barents seas and then examined
the possibility of appropriate remedial actions. The conclusions of the assessment were
published in 1997 and 1998 by the IAEA. The Russian information given in 1992 and at
Holmenkollen in 1993 estimated that when the dumping occurred, it consisted of a total
inventory of 37 PBq (a petabecquerel or PBq is 10 15 Bq) being left in the ocean.
The study found that some of the low-level waste containers had probably leaked be-
cause elevated levels of some radionuclides in sediments could be detected within a few
metres of the containers. However, no measurable increase of radionuclides in the outer
parts of the fjords or in the open Kara Sea was detected. To estimate risk posed by the
dumped reactors and high-level waste, the study examined details concerning the construc-
tion and corrosion characteristics of their containment and developed several scenarios that
could result in release of radionuclides to the ocean. They were:

· A slow release scenario occurring from the gradual corrosion of the barriers, waste

containers and the fuel itself.

· Two catastrophic scenarios, causing an instant or accelerated release of the remain-

ing radionuclide inventory.

The scenario release rates were then analysed using knowledge of the environmental be-
haviour of radionuclides to estimate radiation doses for three human population groups;
for the world population; and for flora and fauna. The population groups consisted of an
“extreme exposure” group of seafood consumers, an average north-east Russian population
and a hypothetical groupofsecurity personnel patrolling the foreshore ofthe fjords close to